Inner sole having low frictional portions



Jan. 8, 1963 A. R. STICKLES 3,071,877

INNER SOLE HAVING LOW FRICTIONAL PORTIONS Filed Oct. 19, 1959 mmvrozz. ARTHUR R. STICKLES Q n'l s.

ATTORNEY United States Patent Q P 3,071,877 INNER SOLE HAVING LOW FRICTIONAL PORTIONS Arthur R. Stickies, 10154 Elgin, Huntington Woods, Mich. Filed Oct. 19, 1959, Ser. No. 847,259 3 Claims. (Cl. 36-44) This invention relates to shoes and more particularly to an improved inner sole therefor.

The importance of an inner sole for foot comfort has been well appreciated in the art, and various improvements in the nature and construction of inner soles have been proposed. Particularly, it has been realized that much foot discomfort is attributable to inner soles. Therefore, the search for causes of foot discomfort for which the inner sole is responsible and methods of eliminating such causes by changes in the inner sole construction have been going on for many years. However, this problem is very far from solution, and the search, as well as proposals of improvements in the construction of inner soles cohtinue.

One of such proposals was to provide a sock lining in the form of an inner sole, or a liner covering the entire inner sole, made of material such as cellophane, i.e. cellulose acetate plastic sheet. It was thought that this material, being impervious to moisture and having a smooth glossy surface, would provide the necessary comfort. In spite of such proposal being almost 20 years old, it has not received any appreciable application.

I have found that the above construction, while appreciating some of the advantages of such plastic material, utilized it in such a manner as to create other problems that virtually destroyed all of the advantages which were otherwise secured.

I have found that covering the inside of the shoe or making its inner sole out of plastic material impervious to moisture and having a smooth and glossy surface does produce a pleasant sensation when the shoe is first put on. However, after Wearing such shoes for some time and particularly walking for some distance, such shoe proves to be rather tiring because of the foot slipping therein with each step and moving forward as fas as the construction of other parts of the shoe permits, often causing the large toe to press against the front of the shoe. Such a condition soon produces a rather tiring and unpleasant feeling similar to that produced by a short shoe, the latter difliculty being notoriously one of the most unpleasant that a shoe can create. Furthermore, impervious plastic materials preventing the proper escape of perspiration causes the feet to be rather moist and hot, producing a burning sensation and serious foot fatigue.

One of the objects of the present invention is to provide an improved inner sole or liner for a shoe whereby the above difiiculties and disadvantages are overcome and largely eliminated without introducing other problems destroying or substantially decreasing the desired advantages, as well as without appreciably increasing the costs involved.

Another object of the present invention is to provide an improved inner sole or liner for a shoe, producing foot slippage only at the desired moment of the step cycle and in a desired measure but preventing execessive forward slippage of the foot.

A further object of the present invention is to provide an improved inner sole or liner for a shoe, utilizing the Patented Jan. 8, 1963 material possessing such a low coefiicient of friction as to produce the desired slippage and to retain such property for a sufiiciently long time, a material which is chemically inert, sufiiciently tough, flexible, and moisture resistant,

i.e. absorbing no moisture and, therefore, sanitary.

, an improved inner sole or liner for a shoe which may be incorporated in the shoe construction in the process of its manufacturing or be inserted into a ready made shoe as an inlay or liner available on the market as a separate article of manufacture.

It is an added object of the present invention to provide an improved inner sole or liner for a shoe which is simple in construction, dependable in operation, and is relatively inexpensive to manufacture.

Further objects and advantages of this invention will be apparent from the following description and appended claims, reference being had to the accompanying drawings forming a part of this specification, wherein like reference characters designate corresponding parts in the several views.

FIG. 1 is a perspective view showing an inner sole or an inlay for a shoe, embodying the present invention.

FIG. 2 shows the bottom surface of the inner sole of FIG. 1, when such sole is made for distribution as 21 separate article of manufacture to be inserted in a ready made shoe.

FIG. 3 is a sectional view of the construction of FIG. 2 taken in the direction of the arrows on the section plane passing through the section line 3-3 of FIG. 2.

FIG. 4 is a view similar in part to FIG. 1 but showing a modified construction of my improved inner sole.

FIG. 5 is a perspective view showing a still further modification.

It is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and not of limitation.

In accordance with the invention I provide an inner sole which may be incorporated into the construction of a shoe when the same is manufactured, or which can be made in the form of a liner for a ready-made shoe. The inner sole, made in accordance with the invention, utilizes an impervious plastic material having an exceedingly smooth and slippery surface, which material is also impervious to moisture and gases. This material is used in the construction of the inner sole in such a manner as to produce slippage of the foot primarily as the foot is raised to be brought forward rather than as the foot is stepped on. Furthermore, the construction of the inner sole or liner is such that it prevents the material from interfering with ventilation of the shoe and escape of the perspiration therefrom.

In the drawings there is shown, by way of example,

a number of inner soles or liners embodying the present invention. Referring particularly to FIG. 1, the inner sole illustrated therein comprises a piece of suitable inner sole material, preferably leather. This piece is coextensive with the conventional inner sole, i.e. is of the same size and shape as would be an inner so e or liner for a particular shoe. Genuine leather used for inner soles or liners for good quality shoes has a durable and smooth top surface and yet it possesses sufficient porosity to permit escape of perspiration, a condition of importance for proper foot comfort.

In the front part of the leather piece 10 I provide a piece or strip 11 made of a thin sheet or film of plastic material having a very smooth top surface and impervious to moisture and gases. I prefer to use film of approximately .005" thick made of tetrafluoroethylene resin sometimes referred to in the art as TFE-fluorocarbon resin presently available in the market under the trade-mark Teflon of Du Pont Co. Such material has coefficient of friction which is claimed to be lowest of any solid and is comparable to ice rubbing against ice, with the static and dynamic coeflicients of friction being equal. It is tough and flexible; it is impervious to gases and moisture; it is chemically inert; treated with suitable adhesive, it adheres strongly to leather and other materials.

It is of importance that the strip 11 does not extend throughout the entire surface of the leather piece 10 and particularly that it does not extend to the portion of said piece 10 over which the toes rest. By virtue of such a construction, imperviousness of the piece 11 does not interfere with the escape of perspiration, which perspiration takes place primarily in the toe portion of the foot. It is also of importance that the piece 11 extend in the portion of the leather piece 10 which receives the ball of the foot, i.e. the portion of the foo-t immediately adjacent to the toes. If the piece 11 extended throughout the entire surface of the piece 10, it would produce excessive slippage of the foot, causing fatigue and interfering with the ventilation of the foot and escape of perspiration, thus destroying virtually all of the advantages that can be derived from this material.

The undersurface of the piece 10 is adapted to be attached to the lower portion of the shoe construction, such as the top surface of the sole. If my improved inner sole is incorporated into the shoe construction at the time of its manufacturing, it takes the place of the regular inner sole and its attachment to the lower shoe structure is made in accordance with the methods well known in the art, such as by cementing and the like. On the other hand, if my improved inner sole is sold as a liner to be inserted into a ready-made shoe, its undersurface is provided with a coat of suitable cement, as indicated at 12, and the same is covered with a masking paper to prevent its drying or sticking to its packaging. To facilitate removal of the masking paper, the same may be made in the form of two pieces, such as 13 and 14, which are overlapping in the middle of the piece 10. Because of overlapping, the edge portion 15 of the piece 14 will not be contacting the adhesive portion 12 and, therefore, it is easy to take hold of for removal. To permit easy removal of the piece 13, the layer of adhesive 12 may be interrupted under the edge 16 of the piece 13 as indicated at 17. However, other forms of masking paper pieces, particularly a single piece extending throughout the entire liner, may be used.

By virtue of the above described construction, the first sensation experienced by the user is that putting a shoe on is made much easier. in walking, the wear notices the slippage of the foot in the shoe but this slippage is noticeable primarily as the shoe is raiscd to be brought forward rather than when it is placed down on the ground. Thus, the slippage of the foot is controlled and occurs when it is desired and only to the desired extent. Such restricted or controlled slippage has two important functions. The

controlled movement of the foot within the shoe operates to pump air in and out of the shoe causing the necessary ventilation. Furthermore, since this movement of the foot in the shoe is not taking place solely by resiliency or yielding of the flesh, particularly in the ball of the foot, but occurs in a large measure because of slippage of the foot, its occurrence does not strain the tissue underlying the bone structure of the foot in the ball portion thereof. This condition eliminates burning sensation and formation of callous layers in the skin. The toe portion of the foot is not in contact with the plastic material and, therefore, is not affected thereby as explained above.

FIG. 4 shows a construction similar to the construction of FIG. 1 but including also a piece 20 of plastic similar to piece 11, with said piece 20 being provided in the portion of the piece 10 receiving the heel. Such a construction may be used to eliminate difficulty which the wearer may have with his heel. Under certain conditions it may be desirable to use the liner having only the heel piece 20 but without the piece 11, particularly when used in a short shoe or should excessive slippage be felt for some other reason. While slippage in the construction shown in FIG. 4 is smaller than that which would occur if the entire inner sole was covered with the plastic material, under some conditions it still may be excessive for short shoes. I have found, however, that the construction of FIG. 4 is still advantageous in many instances of heel trouble and upon eliminating the difficulty, the wearer may go to the construction of FIG. 1.

FIG. 5 is similar to the construction of FIG. 1, the main difference being in the leather piece 21 which, in the construction of FIG. 5, extends only to cover the front portion of the shoe. Such a construction is particularly advantageous when my improved inner sole is made as a liner for use in a ready-made shoe which may already have a proper inner sole or lining, and in which providing covering for the heel portion thereof is not necessary or desirable.

It should be understood that use of genuine leather for pieces 10 and 21 is a preferable expedient to attain the full advantages of my improved inner sole or liner. However, use of other materials presently usable for inner soles, particularly in shoes of various quality grades, may also be used providing that such material possesses some measure of porosity and is not wholly impervious.

By virtue of the above disclosed construction, the objects of the present invention and numerous additional advantages are attained.

I claim:

1. An inner sole for a shoe having a sole, said inner sole being the uppermost element of the sole construction and forming the upper surface thereof, said inner sole comprising a layer of unbroken solid sole material of substantially uniform thickness and a strip of a tctrafluoroethylene resin film seamlessly attached to the upper surface of said material to receive the ball of the foot but terminating before reaching the toe-receiving portion of the inner sole.

2. An inner sole for a shoe having a sole, said inner sole being the uppermost element of the sole construction and forming the foot-contacting surface thereof, said inner sole comprising a layer of unbroken leather sole material of substantially uniform thickness and a strip of tetrafluoroethylene resin film seamlessly attached to the upper surface of the inner sole to receive the ball of the foot but terminating before reaching the toe-receiving portion of the inner sole, a layer of adhesive provided on the underside of the inner sole and a sheet of masking paper covering said adhesive.

3. An inner sole for a shoe having a sole, said inner sole being the uppermost element of the sole construction and forming the foot-contacting surface thereof, said inner sole comprising a layer of unbroken leather sole material of substantially uniform thickness and a strip 5 of tetrafluoroethylene resin film seamlessly attached to the portion of the inner sole to receive the ball of the foot but terminating before reaching the toe-receiving portion of the inner sole, and a patch of tetrafluoroethylene resin film covering the heel-receiving portion of the inne:- sole.

References Cited in the file of this patent UNITED STATES PATENTS 1,780,574 Williams Nov. 4, 1930 2,274,205 Mann Feb. 24, 1942 2,318,926 Daniels May 11, 1943 6 2,491,280 Roth Dec. 13, 1949 2,691,814 Tait Oct. 19, 1954 2,865,097 Vollrath et a1. Dec. 23, 1958 2,917,842 Scholl Dec. 22, 1959 2,917,844 Sc'holl Dec. 22, 1959 OTHER REFERENCES Modern Plastics Encyclopedia, 1949, page 582 (copy in Library).

Modern Plastics Encyclopedia, 1955, page 557, 138- Teflon.

Modern Plastics Periodical, vol. 34, January 1957, pages 156 and 162, 36-P.D. 

1. AN INNER SOLE FOR A SHOE HAVING A SOLE, SAID INNER SOLE BEING THE UPPERMOST ELEMENT OF THE SOLE CONSTRUCTION AND FORMING THE UPPER SURFACE THEREOF, SAID INNER SOLE COMPRISING A LAYER OF UNBROKEN SOLID SOLE MATERIAL OF SUBSTANTIALLY UNIFORM THICKNESS AND A STRIP OF A TETRAFLUOROETHYLENE RESIN FILM SEAMLESSLY ATTACHED TO THE UPPER SURFACE OF SAID MATERIAL TO RECEIVE THE BALL OF THE FOOT BUT TERMINATING BBEFORE REACHING THE TOE-RECEIVING PORTION OF THE INNER SOLE. 